[OE-core][scarthgap][PATCH 4/7] gnutls: Fix CVE-2026-42015

[hsimeliere.opensource@witekio.com]

From: "Hugo SIMELIERE (Schneider Electric)" <hsimeliere.opensource@witekio.com>

Pick patch from [1] as mentioned in Debian report in [2].

[1] https://gitlab.com/gnutls/gnutls/-/commit/a3e7c50d3e1761e5ef1d4b225507cab8f2b2c3ca
[2] https://security-tracker.debian.org/tracker/CVE-2026-42015

Signed-off-by: Hugo SIMELIERE (Schneider Electric) <hsimeliere.opensource@witekio.com>
Reviewed-by: Bruno VERNAY <bruno.vernay@se.com>
---
 .../gnutls/gnutls/CVE-2026-42015.patch        | 50 +++++++++++++++++++
 meta/recipes-support/gnutls/gnutls_3.8.4.bb   |  1 +
 2 files changed, 51 insertions(+)
 create mode 100644 meta/recipes-support/gnutls/gnutls/CVE-2026-42015.patch

diff --git a/meta/recipes-support/gnutls/gnutls/CVE-2026-42015.patch b/meta/recipes-support/gnutls/gnutls/CVE-2026-42015.patch
new file mode 100644
index 0000000000..dfc3506ccc
--- /dev/null
+++ b/meta/recipes-support/gnutls/gnutls/CVE-2026-42015.patch
@@ -0,0 +1,50 @@
+From 264da2a72033ed8890105231e5d36263d403ca60 Mon Sep 17 00:00:00 2001
+From: Alexander Sosedkin <asosedkin@redhat.com>
+Date: Mon, 20 Apr 2026 22:42:20 +0200
+Subject: [PATCH] x509/pkcs12_bag: fix off-by-one in bag element bounds check
+
+Appending elements to a PKCS#12 bag had a bounds check that
+prevented adding the 32nd element.
+On the other hand, it is possible to import one that already has 32.
+Subsequent appending then led to writing past the 32-element array,
+smashing its length.
+
+Tighten the check to reject any bag with 32 or more elements.
+
+We'll treat this vulnerability as a Low due to how contrived
+the requirements are: for the code to be vulnerable,
+it needs to append to an imported untrusted unencrypted PKCS#12 structure.
+
+Reported-by: Zou Dikai
+Fixes: #1840
+Fixes: CVE-2026-42015
+Fixes: GNUTLS-SA-2026-04-29-11
+CVSS: 6.1 Medium CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H
+Severity: Low
+
+CVE: CVE-2026-42015
+Upstream-Status: Backport [https://gitlab.com/gnutls/gnutls/-/commit/a3e7c50d3e1761e5ef1d4b225507cab8f2b2c3ca]
+
+Signed-off-by: Alexander Sosedkin <asosedkin@redhat.com>
+(cherry picked from commit a3e7c50d3e1761e5ef1d4b225507cab8f2b2c3ca)
+Signed-off-by: Hugo SIMELIERE (Schneider Electric) <hsimeliere.opensource@witekio.com>
+---
+ lib/x509/pkcs12_bag.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/lib/x509/pkcs12_bag.c b/lib/x509/pkcs12_bag.c
+index 911aeff93..38228613c 100644
+--- a/lib/x509/pkcs12_bag.c
++++ b/lib/x509/pkcs12_bag.c
+@@ -375,7 +375,7 @@ int gnutls_pkcs12_bag_set_data(gnutls_pkcs12_bag_t bag,
+ 		return GNUTLS_E_INVALID_REQUEST;
+ 	}
+ 
+-	if (bag->bag_elements == MAX_BAG_ELEMENTS - 1) {
++	if (bag->bag_elements >= MAX_BAG_ELEMENTS - 1) {
+ 		gnutls_assert();
+ 		/* bag is full */
+ 		return GNUTLS_E_MEMORY_ERROR;
+-- 
+2.43.0
+
diff --git a/meta/recipes-support/gnutls/gnutls_3.8.4.bb b/meta/recipes-support/gnutls/gnutls_3.8.4.bb
index 69f90a3c01..20946c1030 100644
--- a/meta/recipes-support/gnutls/gnutls_3.8.4.bb
+++ b/meta/recipes-support/gnutls/gnutls_3.8.4.bb
@@ -48,6 +48,7 @@ SRC_URI = "https://www.gnupg.org/ftp/gcrypt/gnutls/v${SHRT_VER}/gnutls-${PV}.tar
            file://CVE-2026-33845-pre.patch \
            file://CVE-2026-33845.patch \
            file://CVE-2026-3833.patch \
+           file://CVE-2026-42015.patch \
            "
 
 SRC_URI[sha256sum] = "2bea4e154794f3f00180fa2a5c51fe8b005ac7a31cd58bd44cdfa7f36ebc3a9b"
-- 
2.43.0